In short, any way to limit number of httpd processes on a per-domain basis?

I'm guessing not I've seen a lot of similar requests based on per-user rather than per-domain, and that doesn't seem easy as well. I can try variations on /etc/security/limits.conf which sort of address the issue, since I do use suPHP and thus PHP pages run the process as the user, so limiting nproc on a per-user might work. It won't work on non-PHP pages, but any domain serving strictly *.html pages, I hope, aren't my limiting factor or problem

These are all non-SSL domains using the same primary IP address, so I can't do iptables stuff on a per-target-IP basis (and even then, it's not exactly what I want.)

I haven't done the rLimit* directives, since they really only affect children of httpd and not the httpd children themselves (although I suppose it doesn't hurt to have values for them anyway, just in case.)

The above are generally what I've seen fly by on various forum postings in the past, and all roughly-sorta-kinda get to what I want to do. I was just hoping there might be some overlooked cPanel magic

I'm trying to keep our cPanel relatively generic, so I haven't installed any of the various 3rd-party things such as CSF, despite their high recommendations here on the forums. For us, moving to CloudLinux (which also seems to get high recommendations) isn't quite (yet) an option. If CL is really that good (I don't know anything about it, coming from a RHEL-standard workshop), I might be able to make a case the work/learning is worth it. But that's a separate issue, not for this thread